In a rambling manifesto, Dorner writes about racial slights within the Los Angeles Police Department, where he worked until being fired in 2008.

Authorities have already beefed up security for several police officials mentioned in the manifesto as the source of his anger.

In the manifesto, which he posted on a Facebook page, Dorner writes: "I grew up in neighborhoods where blacks make up less than 1%. My first recollection of racism was in the first grade at Norwalk Christian elementary school in Norwalk."

He says a fellow student there called him the N-word on the playground.

"My response was swift and non-lethal," Dorner writes. "I struck him with a fast and hard kick. He cried and reported it to a teacher. The teacher reported it to the principal."

Dorner says the principal "swatted" the student for using the word, but then "for some unknown reason swatted me for striking the student who had used the word."

"How dare you swat me for standing up for my rights for demanding that I be treated as an equal human being," Dorner goes on.

He adds, "That day I made a life decision that i will not tolerate racial derogatory terms spoken to me."